dep-upgrade

name	dep-upgrade
description	Analyze a major version dependency upgrade: summarize breaking changes, assess project impact, and propose new features to adopt. Outputs a plan.md and executes the upgrade.

Analyze and execute the major version upgrade for: $ARGUMENTS

1. Analyze — fetch the official migration guide via WebFetch; apply the checklist in instructions.md
2. Generate plan — create docs/dev-notes/YYYY-MM-DD/{package}-upgrade/plan.md with breaking changes, impact, and new features; stop and ask for confirmation
3. Execute — update package.json, run pnpm install && pnpm lint && pnpm check && pnpm test:unit; update the plan checklist when done